Control for vapor discharge tubes and electric arcs



June 28, 1949. E. H. HAUG 2,474,525

CONTROL FOR VAPOR DISCHARGE TUBES AND ELECTRIC ARCS Filed April.3, 19442 Sheets-Sheet 1 4 ME 2/ 1 7 ,5 l0 8 F/q- "I IN V EN TOR.

June 28, 1949. E. H. HAUG 2,474,525

CONTRQL FOR VAPOR S CHARGE TUBES AND ELECT ARCS Filed April 5, 1944 2Sheets-Sheet 2 ymn TTT y IN VEN TOR.

Patented June 28, 1949 coN'rao FOR varo R DISCHARGE TUBES AND ELECTRICARCS Eugene H. Hang, Glenooe, 111., assignor, by direct and memeassignments, to Modern Controls, Inc., Chicago, 111., a corporation ofDelaware Application April 3, i944, Serial No. 529,253

1 5 Claims.

My invention relates to an electric control circuit for vapor dischargetubes and electric arcs, and more particularly to such loads having anegative resistance characteristic and requiring a dis- .torted voltageor current wave in their operation.

Heretofore there have been proposed several arrangements of controlcircuits, such as the high leakage transformer or series reactors. Allthese controls have the defect of taking from the supply circuit eithera distorted current wave or voltage wave, thereby creating a low powerfactor in the supply circuit, and causing radio and telephoneinterference. In certain arrangements of the prior art attempt has beenmade to overcome such defect by the use of shunt capacitors across thesupply circuit. If capacity reactance be paralleled in the primarysupply circuit in an effort to improve the power factor, the optimumpower factor will only be obtained when the fundamental component of thecurrent wave is in phase with the impressed sinusoidal voltage wave.Under these conditions the harmonic components of the current wave willremain unaltered, since with a sinusoidal impressed voltage capacitancethey can draw only current possessing a sinusoidal wave. In other words,shunt capacitance cannot, under any condition, correct power factor dueto a distorted current and voltage wave.

It is an object of my invention, therefore, to

. provide an improved alternating current control system forimproving-the power factor due to cur-- rent and voltage wave formdistortion.

It is another object of my invention to provide an alternating currentcontrol systemwhich will not distort the current or voltage wave in thesupply circuit, although the load requires a distorted voltage wave,thereby eliminating radio and telephone interference.

It is another object of my invention to provide an improved alternatingcurrent control system which has the advantage of higher apparatuseconomy.

It is another object of my invention to provide an improved alternatingcurrent control system which is conducive to long tube and lamp life.

It is another object of my invention to provide an improved alternatingcurrent control system which eliminates the use of high voltages onthose parts of the apparatus which are accessible to the operator,thereby providing a personal safety factor.

These and other objects that will be made apparent throughout thefurther description of my invention are obtained by use of the controlsystom hereinafter described and illustrated in the accompanyingdrawings, wherein Figure No. 1 is a a wiring diagram of my controlsystem for use in operating cold cathode vapor discharge tubes and highvoltage arcs.

Figure No.2 is an oscillograph showing the distorted current wave in thesupply circuit and the phase relation of this distorted current wave inrelation to the supply voltage when using present day equipment.

Figure No. 3 is an oscillograph showing the non-distorted current wavein the supply circuit and the phase relation of this non-distorted cur--rent wave with reference to the supply voltage wave when operating theload on my new improved control system.

Figure No. 4 is a wiring diagram of my contro system for use inoperating hotcathode vapor discharge tubes and low voltage arcs.

Figure No. 5 is a wiring diagram of my control system similar to thatshown in Figure No. 4 except that the air gap is in the center commoncore instead of the cores of each window, and the reactance value ofeach coil is controlled by tap arrangements.

Referring to Figure No. 1, I and 2 are the alternating current supplylines. Line I is connected to coil 4 of the special double reactor i2.Coil I has its other end connected to line 5, which is in turn connectedto line 9.. A capacitor! is connected between lines 9 and 2 by means oflines 6 and 1. C011 2| is connected in series circuit relation with coil4 by means of lines 5, 9 and i0. Coil II is mounted on the core ofspecial double reactor l2. Transformer l6 has one end of its primary itconnected to coll 2| by means of line H, and the other end of primary I4is connected toline 2. The secondary i5 of transformer I8 is connectedto load l9 by means of lines l1 and It.

The operation of Figure No. 1 is as follows: the alternating currentsupply, which is of constant potential characteristic, is fed to'reactorl2 and capacitor 1 in a manner that constant current is produced in theprimary ll of transformer IS. The production of this constant current iscontrolled by the air gaps 3 and ll of special reactor II in such amannerthat the voltage across capacitor 8 tends to regulate the currentto the primary of transformer it. It will be further noted that in thisarrangement the two coils of special double reactor I2 are in seriescircuit relation with one end of primary ll of transformer It. Thecapacitor 8 is midtapped between coils 2| and 4 in a manner to act as aT connection wave. trap. This form of of the air gaps I and I3. has theelectrical char-' acteristics of producing sinusoidal waves of currentsand voltages when fed from a distorted current or voltage wave.Furthermore, since special double reactor I2 in conjunction withcapacitor 9 acts as a resonant form of constant potential to constantcurrent device, the voltage across load II will always be of such avalue that it will readily restrike the are at a very early period ofeach alternation of the alternating current supply.

Figure No. 2 shows the wave form of the current as indicated at I andthe voltage as indicated at 2. When high reactance and high leakagetransformers are connected to lines having sinusoidal voltage waves, acurrent wave of non-- sinusoidal form will flow.

Figure No. 3 shows the wave form of the current as indicated at I andthe voltage as indicated at 2, when my control is used. It will be notedthat the current wave I of Figure No. 2 lags the voltage wave by about'72 degrees (31% power factor) and contains both the 3rd and 5thharmonics of appreciable magnitude, while in Figure No. 3 the currentwave I is sinusoidal in characteristic and that this sinusoidal currentwave I is in phase with the sinusoidal voltage wave 2.

Referring to .Figure No. 4 the alternating current supply lines I and 2,the special double reactor I2, and the capacitor 9, are similarlyconnected as in Figure No. 1, the difference between Figure No. 1 andFigure No. 4 being that while Figure No. 1 has a step up transformer I6and a cold cathode tube I9, Figure No. 4 has no step up transformer tothe load, which is a hot cathode tube having two heater type electrodes22 and 23 at opposite ends, with a starting device I8 connected toheatertype electrode 22 by line H, and to heater electrode 22 by lineI9. Since load 29 is a hot cathode tube with heater electrodes 22 and29, the voltage consumed is very much lower than the voltage consumed bythe cold cathode tube I9 of Figure No. 1, and therefore the hot cathodetube 29 of Figure No. 4 does not require a step up transformer." asindicated in Figure No. 1.

While I have described what I at present consider the preferredembodiment of my invention, it will be obvious to those skilled in theart that various changes and modifications may be made without departingfrom my invention, and I therefore aim in the appended claims to coverall such changes and modifications as fall within the true spirit andscope of my invention.

Because on open circuit in any constant current device the voltage willgo to infinity, it becomes important to protect the constant currentnetwork and the load circuit against such high potential. Therefore thetransformer I6 must be especialiy constructed so that on full load, theop-' erator is, instead of bein on the straight portion of thesaturation flux current as is usual, on the knee of the curve. There aremany ways in which such a transformer may be constructed, special gradesof core material may be used or the core may be restricted but in anyevent some such special arrangement must be provided with a circuit suchas the one I disclose whereby the open circuit voltage of the constantcurrent network will be held down to a safe and reasonable limitingvalue and any structure that will insure this by limiting the saturationof the core will accomplish this purpose:

The use of the double reactor with an air gap of different value in eachcore is highly important because with respect to the coil on the intakeside of the circuit, namely the coil 4, you get any relationship to thecoil on the transformer side of the circuit, namely the coil 2I, thefollowing result that coil 4 will produce a constant current inconjunction with the capacitor and coil H in conjunction with thecapacitor produces a wave trap so that the supply line will not beadversely affected by harmonics produced in the load.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In combination with a constant potential to constant current controldevice, a constant potential alternating current supply, a doublereactor having two windows, a capacitor, a current transformer, and aload circuit, said double reactor having two coils mounted one each onthe core of each window, and said double reactor having an air gap inthe core of each of said windows, said capacitor being connected betweenthe two coils of said double reactor and one side of said constantpotential alternating current supply, the two air gaps being ofdifferent value, said current transformer having its primary connectedto the output circuit of said constant potential to constant currenttransformation device and its secondary connected to said load circuit,said reactor having a tap arrangement so that the constant current inthe load circuit may be set to any desired value, and said currenttransformer having its core so constructed that upon an open circuit insaid load circuit the magnetic fiux density is so limited that thevoltage across the secondary of said current transformer is held to asafe value.

2. In combination with a constant potential to constant current controldevice, a constant potential alternating current supply, a doublereactor having two windows, a capacitor, and a load, said double reactorhaving two coils mounted one each on the core of each window, and saiddouble reactor having an air gap in the core of each of said windows,said capacitor being connected between I the two coils of said doublereactor and one side of said constant potential alternating currentsupply, the two air gaps being of different value.

3. In combination with a constant potential to constant current controldevice, a constant potential alternating current supply, a doublereactor having two windows, a capacitor, and a load, said double reactorhaving two coils mounted one each on the core of each window, and saiddouble reactor having an air gap in the center core, said capacitorbeing connected between the two coils of said double reactor and oneside of said constant potential alternating current supply.

4. In combination with a constant potential to constant current controldevice, a constant poten-- tial alternatin current supply, a doublereactor having two windows, a capacitor, a current transformer, and aload circuit, said double reactor having two coils mounted one each onthe core of each window, said capacitor being connected between the twocoils of said double reactor and one side of said constant potentialalternating current supply, each coil of the double reactor having adifferent reactance value, one coil serving with the capacitance as awave trap, the other serving with the capacitance to provide constantcurrent for the transformer.

5. In combination with a constant potential to constant current controldevice, a constant potential alternating current supply, a doublereactor having two windows, a capacitor, and a load circuit, said doublereactor having two coils mounted 5 6 one each on the core of eachwindow, said-capaci- FER tor being connected between the two coils ofENCES CITED said double reactor and one side of said constant Thefollflwmg references are of record n t e potential alternating currentsupply, each coil file of this p nt: of the double reactor having adifierent reactance 5 UNITED STATES PATENTS value, one c011 serving withthe capacitance as a wave trap, the other serving with the capacitanceNumber Name Date to provide constant current for the transformer.2,063,316 Falkas J 19, 1937 2,179,353 Schmutz et a1 NOV. 7, 1939 EUGENEHAUG 10 2,221,456 Pohm et ai Nov. 12, 1940 2,226,041 Young Dec. 24, 19402,351,681 Haug June 20, 1944

